Does Go's sqlc supports join?

Question

I was reading the documentation for SQLC from https://docs.sqlc.dev/en/latest/howto/query_count.html. I wanted to use this in my project. However, I'm not seeing any documentation related to joining operations on the tables. Is it really possible in SQLC. If yes where I could find the documentation or reference?

Answer 1

A commit like "cdf7025: Add MySQL json test" (or "456fcb1 Add MySQL test for SELECT * JOIN") suggests joins are supported.

2021: But it is true, as mentioned in issue 643, that queries with JOINs are for now not documented yet.

2023: the same issue 643 now (Sept. 2023) includes a reference to the new documentation (thanks to Kyle Gray):

Embedding structs

Embedding allows you to reuse existing model structs in more queries, resulting in less manual serialization work. First, imagine we have the following schema with students and test scores.

CREATE TABLE students (
  id   bigserial PRIMARY KEY,
  name text NOT NULL,
  age  integer NOT NULL
);

CREATE TABLE test_scores (
  student_id bigint NOT NULL,
  score      integer NOT NULL,
  grade      text NOT NULL
);

We want to select the student record and the scores they got on a test. Here's how we'd usually do that:

-- name: ScoreAndTests :many
SELECT students.*, test_scores.*
FROM students
JOIN test_scores ON test_scores.student_id = students.id
WHERE students.id = ?;

When using Go, sqlc will produce a struct like this:

type ScoreAndTestsRow struct {
  ID        int64
  Name      string
  Age       int32
  StudentID int64
  Score     int32
  Grade     string
}

With embedding, the struct will contain a model for both tables instead of a flattened list of columns.

-- name: ScoreAndTests :many
SELECT sqlc.embed(students), sqlc.embed(test_scores)
FROM students
JOIN test_scores ON test_scores.student_id = students.id
WHERE students.id = ?;

type ScoreAndTestsRow struct {
  Student   Student
  TestScore TestScore
}

---

And discussion 363 points to the changelog for sqlc.embed.